Long-term television viewing patterns and gray matter brain volume in midlife

Abstract

The purpose of this study was to investigate whether long-term television viewing patterns, a common sedentary behavior, in early to mid-adulthood is associated with gray matter brain volume in midlife and if this is independent of physical activity. We evaluated 599 participants (51% female, 44% black, mean age 30.3 ± 3.5 at baseline and 50.2 ± 3.5 years at follow-up and MRI) from the prospective Coronary Artery Risk Development in Young Adults (CARDIA) study. We assessed television patterns with repeated interviewer-administered questionnaire spanning 20 years. Structural MRI (3T) measures of frontal cortex, entorhinal cortex, hippocampal, and total gray matter volumes were assessed at midlife. Over the 20 years, participants reported viewing an average of 2.5 ± 1.7 h of television per day (range: 0–10 h). After multivariable adjustment, greater television viewing was negatively associated with gray matter volume in the frontal (β = − 0.77; p = 0.01) and entorhinal cortex (β = − 23.83; p = 0.05) as well as total gray matter (β = − 2.09; p = 0.003) but not hippocampus. These results remained unchanged after additional adjustment for physical activity. For each one standard deviation increase in television viewing, the difference in gray matter volume z-score was approximately 0.06 less for each of the three regions (p < 0.05). Among middle-aged adults, greater television viewing in early to mid-adulthood was associated with lower gray matter volume. Sedentariness or other facets of television viewing may be important for brain aging even in middle age.

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https://doi.org/10.1007/s11682-021-00534-4
ORIGINAL RESEARCH
Long‑term television viewing patterns andgray matter brain volume
inmidlife
RyanJ.Dougherty1· TinaD.Hoang2· LenoreJ.Launer3· DavidR.Jacobs4· StephenSidney5· KristineYae2,6
Accepted: 2 August 2021
© The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2021
Abstract
The purpose of this study was to investigate whether long-term television viewing patterns, a common sedentary behavior, in
early to mid-adulthood is associated with gray matter brain volume in midlife and if this is independent of physical activity.
We evaluated 599 participants (51% female, 44% black, mean age 30.3 ± 3.5 at baseline and 50.2 ± 3.5years at follow-up
and MRI) from the prospective Coronary Artery Risk Development in Young Adults (CARDIA) study. We assessed televi-
sion patterns with repeated interviewer-administered questionnaire spanning 20years. Structural MRI (3T) measures of
frontal cortex, entorhinal cortex, hippocampal, and total gray matter volumes were assessed at midlife. Over the 20years,
participants reported viewing an average of 2.5 ± 1.7h of television per day (range: 0–10h). After multivariable adjust-
ment, greater television viewing was negatively associated with gray matter volume in the frontal (β = − 0.77; p = 0.01) and
entorhinal cortex (β = − 23.83; p = 0.05) as well as total gray matter (β = − 2.09; p = 0.003) but not hippocampus. These
results remained unchanged after additional adjustment for physical activity. For each one standard deviation increase in
television viewing, the difference in gray matter volume z-score was approximately 0.06 less for each of the three regions
(p < 0.05). Among middle-aged adults, greater television viewing in early to mid-adulthood was associated with lower gray
matter volume. Sedentariness or other facets of television viewing may be important for brain aging even in middle age.
Keywords Lifestyle factors· Sitting time· Volumetric MRI· Epidemiology· Cohort studies
Introduction
While it is generally accepted that a physically active life-
style is important for cognitive and brain health (Barnes &
Yaffe, 2011; Dougherty etal., 2016, 2017, 2021; Erickson
etal., 2014; Hamer & Chida, 2009; Yaffe etal., 2001), sed-
entary behavior has increasingly become a public health
focus due to evidence that it may impart unique risk for
chronic diseases (Dunstan etal., 2012; Katzmarzyk etal.,
2009). Sedentary behaviors are defined as any waking
behavior characterized by low levels of energy expenditure,
while in a seated, reclined or lying posture (Ainsworth etal.,
2000). Although a few studies have investigated sedentary
lifestyle on cognitive function and dementia risk in older
adults (Barnes & Yaffe, 2011; Falck etal., 2017; Wheeler
etal., 2017), much less is known how sedentary behaviors
influence measures of brain health in midlife (Voss etal.,
2014).
Reduction in gray matter volume measured by brain mag-
netic resonance imaging (MRI) is a marker of brain health
that often precedes cognitive impairment (Iturria-Medina
etal., 2016; Jack etal., 2018). Gray matter declines (i.e.,
atrophies) during midlife (Raz etal., 2005; Resnick etal.,
2003) and longitudinal patterns of atrophy predict future
cognitive function and dementia onset (Allison etal., 2019;
Driscoll etal., 2009). Therefore, strategies that preserve
gray matter volume in midlife may mitigate the progression
of cognitive decline. The few recent studies on the effects
* Ryan J. Dougherty
rdoughe7@jhu.edu
1 Department ofEpidemiology, Johns Hopkins Bloomberg
School ofPublic Health, Johns Hopkins University, 2024 E.
Monument St., Suite 2-700, Baltimore, MD21205, USA
2 San Francisco VA Health Care System, SanFrancisco, CA,
USA
3 National Institute onAging, Bethesda, MD, USA
4 University ofMinnesota, Minneapolis, MN, USA
5 Kaiser Permanente Division ofResearch, Oakland, CA, USA
6 University ofCalifornia, San Francisco, SanFrancisco, CA,
USA
/ Published online: 6 September 2021
Brain Imaging and Behavior (2022) 16:637–644
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